Hey, I've snowboarded occasionaly (high snowboard rental rates) and liked it. Now I'm wondering how much it would cost to get all the equipment I'd need. So how much might it cost ti get all the equipment, but still have a fair ammount of quality?

Good boards are around $200-$400, good boots are around $200, and good bindings are around $200. Those are just estimates, you can probably find some better deals. Don't buy gear until you're certain that this is something that you will continually do.

If you don't snowboard a whole ton, the main benefit of buy equipment is quite literally having your own equipment. You can get used to your stance and your board and you'll progress a lot faster than if you're always on rentals.
Like the above posters said though, it's pretty expensive. Don't make the mistake of skimping out on boots either. That'll kill off your drive for snowboarding faster than anything else.